<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <script src="../react18/react.development.js"></script>
  <script src="../react18/react-dom.development.js"></script>
  <script src="../react18//babel.min.js"></script>
</head>
<body>
  <div id="app"> </div>
  <script type="text/babel">
    function Content(){
      return <p>我是内容</p>
    }

     class Title extends React.Component{
      // 类式组件必须拥有一个render方法,当组件被使用的时候  组件实例会找render方法拿返回的虚拟DOM
      render(){
        return <h1>标签</h1>
      }
     }

     class App extends React.Component{
      render(){
        return (
          <div>
            <Title/>
            <hr/>
            <Content/>
            </div>
        )
      }
     }


     const root=ReactDOM.createRoot(document.getElementById("app"))
     root.render(<App/>)


  </script>
</body>
</html>